Nutritional formulas today are well known for a variety of nutritional or disease specific applications in infants, children and adults. These formulas most typically contain a balance of proteins, carbohydrates, lipids, vitamins, and minerals tailored to the nutritional needs of the intended user, and include product forms such as ready-to-drink liquids, reconstitutable powders, nutritional bars, and many other forms.
Many nutritional formulas also commonly contain a variety of polyunsaturated fatty acids (PUFA) as part of the lipid component of the overall nutrient system, examples of which include omega-3 (n-3) fatty acids such as alpha-linolenic acid (C18:3n-3), stearidonic acid (C18:4n-3), eicosapentaenoic acid (C20:5n-3), docosapentaenoic acid (C22:5n-3), and docosahexaenoic acid (C22:6n-3), and omega-6 (n-6) fatty acids such as linoleic acid (C18:2n-6), gamma-linolenic acid (C18:3n-6), eicosadienoic acid (C20:2n-6), arachidonic acid (C20:4n-6), and di-homo-gamma-linolenic acid (C20:3n-6). A growing body of evidence now suggest that diets containing sufficient amounts of certain long chain polyunsaturated fatty acids may be beneficial for the maintaining overall health, and may also be helpful for treating or preventing a variety human diseases or afflictions. Certain long chain polyunsaturated fatty acids have been shown to be beneficial in the prevention and/or management of cardiovascular disease, rheumatoid arthritis, depression, Alzheimer's, ulcers, cancer, hyperactivity, asthma, or other diseases or conditions responsive to anti-inflammatory effects.
Arachidonic and docosahexaenoic acids in particular have been shown to provide beneficial effects in preterm infants such as enhanced brain and vision development, and are now commonly found in many commercially available infant formulas such as Similac® Advance® Infant Formula and Isomil® Advance® Infant formula, both of which are available from Ross Products Division, Abbott Laboratories, Columbus, Ohio, USA.
These polyunsaturated fatty acids, however, tend to be more sensitive to oxidation than many other ingredients commonly found in nutritional formulas. Due to their chemical structure, exposure to heat and atmospheric levels of oxygen can cause a series of chemical reactions about their carbon:carbon double bonds resulting in free radical formation. These free radicals can continue to break down the polyunsaturated fatty acids in an auto-oxidative process, which results in the development of undesirable off-flavors and odors and the eventual degradation of the beneficial polyunsaturated fatty acids. These polyunsaturated fatty acids are especially susceptible to oxidation when subjected to elevated temperatures during processing or storage.
Oxidative stability has become especially challenging when formulating a nutritional liquid containing the relatively high concentrations of polyunsaturated fatty acids often needed to obtain a therapeutic response. Allowing even some oxidation in these products often results in a highly objectionable flavor and aroma, the characteristics of which are often described as fishy, eggy, or otherwise having a rancid flavor or smell, depending upon the particular polyunsaturated fatty acid used in the formulation.
Methods of controlling the undesirable oxidation of polyunsaturated fatty acids in a nutritional product include processing or manufacturing controls to limit conditions such as elevated temperatures, exposure to ultraviolet light, exposure to oxygen and other factors that can promote oxidation. All such methods almost always include the concurrent formulation with one or more anti-oxidant additives such as ascorbic acid or ascorbyl palmitate, tocopherols, beta-carotene, or others. Although these methods are often highly effective in reducing much of the undesirable oxidation that would otherwise occur, they are often not as effective when applied to liquid nutritional compositions that contain the relatively high polyunsaturated fatty acid concentrations often needed to achieve a desired therapeutic effect.
It has now been found, however, that liquid nutritionals containing relatively high polyunsaturated fatty acids can now be formulated with improved oxidative stability and flavor masking, without the need to reduce fatty acid concentrations in order to achieve the desired oxidative stability and thus, acceptable flavor. This has been accomplished by preparing the liquid nutritional so as to comprise: (A) a carbohydrate component; (B) a lipid component having from about 0.1% to about 10% of an n-3 fatty acid, n-6 fatty acid, or combinations thereof, by weight of the liquid composition; (C) a protein component having from about 15% to about 50% of a whey protein fraction by weight of the total protein in the liquid composition, and (D) a limonene-containing material, and/or (E) a flavor masking agent comprising one ore more of cranberry oil, peppermint oil, rosemary oil, or ginger oil.
It has also been found that the liquid nutritionals of the present invention can be aseptically packaged for improved oxidative stability, reduction in the development of off-flavors, and extended shelf life at room temperature.
It is therefore an object of the present invention to provide nutritional formulas containing relatively high concentrations of polyunsaturated fatty acids with improved oxidative stability, flavor, and aroma. It is a further object of the present invention to provide such a formulation without the need to reduce polyunsaturated fatty acid concentrations. It is a further object of the present invention to provide such a formulation comprising a defined protein matrix in combination with a limonene-containing material or selected masking agents for enhanced oxidative stability, flavor, and aroma of the finished product.
These and other objects of the present invention are described and shall be apparent from the description as set forth hereinafter.